<template>
	<div class="upload-file">
		<el-upload
			ref="upload"
			multiple
			:action="uploadFileUrl"
			:before-upload="handleBeforeUpload"
			:file-list="fileList"
			:limit="limit"
			:on-error="handleUploadError"
			:on-exceed="handleExceed"
			:on-success="handleUploadSuccess"
			:show-file-list="false"
			:headers="headers"
			class="upload-file-uploader"
		>
			<!-- 上传按钮 -->
			<el-button size="mini" type="primary">选取文件</el-button>
			<!-- 上传提示 -->
			<div v-if="showTip" slot="tip" class="el-upload__tip">
				请上传
				<template v-if="fileSize"> 大小不超过 <b style="color: #f56c6c">{{ fileSize }}MB</b> </template>
				<template v-if="fileType"> 格式为 <b style="color: #f56c6c">{{ fileType.join("/") }}</b> </template>
				的文件
			</div>
		</el-upload>

		<!-- 文件列表 -->
		<transition-group class="upload-file-list el-upload-list el-upload-list--text" name="el-fade-in-linear" tag="ul">
			<li v-for="(file, index) in fileList" :key="file.url" class="el-upload-list__item ele-upload-list__item-content">
				<el-link :href="`${file.url}`" :underline="false" target="_blank">
					<span class="el-icon-document"> {{ getFileName(file.name) }} </span>
				</el-link>
				<div class="ele-upload-list__item-content-action">
					<el-link :underline="false" type="danger" @click="onDeleteBtn(index)">删除</el-link>
				</div>
			</li>
		</transition-group>
	</div>
</template>

<script>
    import { getAccessToken } from '@/utils/auth';

    export default {
        name: 'FileUpload',
        props: {
            // 值
            value: {
                type: [String, Object, Array],
                default: ''
            },
            // 数量限制
            limit: {
                type: Number,
                default: 5
            },
            // 大小限制(MB)
            fileSize: {
                type: Number,
                default: 5
            },
            // 文件类型, 例如['png', 'jpg', 'jpeg']
            fileType: {
                type: Array,
                default: () => ['doc', 'xls', 'ppt', 'txt', 'pdf']
            },
            // 是否显示提示
            isShowTip: {
                type: Boolean,
                default: true
            }
        },
        data() {
            return {
                number: 0,
                uploadList: [],
                uploadFileUrl: '', // 请求地址
                headers: { Authorization: 'Bearer ' + getAccessToken() }, // 设置上传的请求头部
                fileList: []
            };
        },
        watch: {
            value: {
                handler(val) {
                    if (val) {
                        let temp = 1;
                        // 首先将值转为数组
                        const list = Array.isArray(val) ? val : this.value.split(',');
                        // 然后将数组转为对象数组
                        this.fileList = list.map(item => {
                            if (typeof item === 'string') {
                                item = { name: item, url: item };
                            }
                            item.uid = item.uid || new Date().getTime() + temp++;
                            return item;
                        });
                    } else {
                        this.fileList = [];
                        return [];
                    }
                },
                deep: true,
                immediate: true
            }
        },
        computed: {
            // 是否显示提示
            showTip() {
                return this.isShowTip && (this.fileType || this.fileSize);
            }
        },
        methods: {
            // 上传前校检格式和大小
            handleBeforeUpload(file) {
                // 校检文件类型
                if (this.fileType) {
                    let fileExtension = '';
                    if (file.name.lastIndexOf('.') > -1) {
                        fileExtension = file.name.slice(file.name.lastIndexOf('.') + 1);
                    }
                    const isTypeOk = this.fileType.some((type) => {
                        if (file.type.indexOf(type) > -1) return true;
                        return !!(fileExtension && fileExtension.indexOf(type) > -1);
                    });
                    if (!isTypeOk) {
                        this.$modal.msgError(`文件格式不正确, 请上传${this.fileType.join('/')}格式文件!`);
                        return false;
                    }
                }
                // 校检文件大小
                if (this.fileSize) {
                    const isLt = file.size / 1024 / 1024 < this.fileSize;
                    if (!isLt) {
                        this.$modal.msgError(`上传文件大小不能超过 ${this.fileSize} MB!`);
                        return false;
                    }
                }
                this.$modal.loading('正在上传文件，请稍候...');
                this.number++;
                return true;
            },
            // 文件个数超出
            handleExceed() {
                this.$modal.msgError(`上传文件数量不能超过 ${this.limit} 个!`);
            },
            // 上传失败
            handleUploadError() {
                this.$modal.msgError('上传图片失败，请重试');
                this.$modal.closeLoading();
            },
            // 上传成功回调
            handleUploadSuccess(res) {
                // edit by 芋道源码
                this.uploadList.push({ name: res.data, url: res.data });
                if (this.uploadList.length === this.number) {
                    this.fileList = this.fileList.concat(this.uploadList);
                    this.uploadList = [];
                    this.number = 0;
                    this.$emit('input', this.listToString(this.fileList));
                    this.$modal.closeLoading();
                }
            },
            // 删除文件
            onDeleteBtn(index) {
                this.fileList.splice(index, 1);
                this.$emit('input', this.listToString(this.fileList));
            },
            // 获取文件名称
            getFileName(name) {
                if (name.lastIndexOf('/') > -1) {
                    return name.slice(name.lastIndexOf('/') + 1);
                } else {
                    return '';
                }
            },
            // 对象转成指定字符串分隔
            listToString(list, separator) {
                let strs = '';
                separator = separator || ',';
                for (const i in list) {
                    strs += list[i].url + separator;
                }
                return strs !== '' ? strs.substr(0, strs.length - 1) : '';
            }
        }
    };
</script>

<style scoped lang="scss">
.upload-file-uploader {
  margin-bottom: 5px;
}
.upload-file-list .el-upload-list__item {
  border: 1px solid #e4e7ed;
  line-height: 2;
  margin-bottom: 10px;
  position: relative;
}
.upload-file-list .ele-upload-list__item-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: inherit;
}
.ele-upload-list__item-content-action .el-link {
  margin-right: 10px;
}
</style>
